The Necessity for Routine Pre-operative Ultrasound Mapping Before Arteriovenous Fistula Creation: A Meta-analysis.

OBJECTIVE/BACKGROUND: Existing guidelines suggest routine use of pre-operative color Doppler ultrasound (DUS) vessel mapping before the creation of arteriovenous fistulae (AVF); however, there is controversy about its benefit over traditional clinical examination or selective ultrasound use. METHODS: This was a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing routine DUS mapping before the creation of AVF with patients for whom the decision for AVF placement was based on clinical examination and selective ultrasound use. A search of MEDLINE/PubMed, SCOPUS, and the Cochrane Library was carried out in June 2014. The analyzed outcome measures were the immediate failure rate and the early/midterm adequacy of the fistula for hemodialysis. Additionally, assessment of the methodological quality of the included studies was carried out. RESULTS: Five studies (574 patients) were analyzed. A random effects model was used to pool the data. The pooled odds ratio (OR) for the immediate failure rate was 0.32 (95% confidence interval [CI] 0.17-0.60; p < .01), which was significantly in favor of the DUS mapping group. The pooled OR for the early/midterm adequacy for hemodialysis was 0.66 (95% CI 0.42-1.03; p = .06), with a trend in favor of the DUS mapping group; however, subgroup analysis revealed that routine DUS mapping was more beneficial than selective DUS (p < .05). CONCLUSION: The available evidence, based mainly on moderate quality RCTs, suggests that the pre-operative clinical examination should always be supplemented with routine DUS mapping before AVF creation. This policy avoids negative surgical explorations and significantly reduces the immediate AVF failure rate.

The hemodynamic impact of misalignment of fenestrated endografts: a computational study.

OBJECTIVE: The hemodynamic consequences of misaligned stent-grafts (SG) in fenestrated endografts (EG) have not been adequately studied. Our aim was to study the hemodynamic effects of positional variations of SG, investigating the potential influence on the total displacement forces acting on the EG and the shear stress values at the stented segments. METHODS: This was a computational study. An idealized EG model with two renal fenestrations was computationally reconstructed and centrally extended up to the suprarenal level to treat a suprarenal aneurysm. The misalignment of SG was represented by a variable take-off angle between the SG and the EG centerline axis, corresponding to angles of 90°, 176°, 142°, 38°, and 4°, respectively. Accordingly, the maximum EG displacement forces and the shear stress within the stented segments were calculated, using commercially available software. RESULTS: The variable positions of the SG caused no effect on the maximum displacement force acting on the EG, being quite steady and equal to 5.55 N. On the contrary, the values of maximum shear stress acting on the stented segments were influenced by their orientation. The narrow transition zone between the distal end of the mating stent and the target artery showed higher stresses than any other segment. The right-angle take off SG position (90°) was associated with the lowest stresses (12.5 Pa), whereas the highest values were detected at 38° and 142° (16.5 and 16.1 Pa, respectively). The vessel segments distal to the SG exhibited constantly lower stress values (1.9-2.2 Pa) than any other segment. CONCLUSION: We detected differences in the values of shear stress exerted on the stented arteries, depending on different positions that SG can adapt after the deployment of fenestrated EG. The pathophysiologic implication of our findings and their potential association with clinical events deserve further investigation and clinical validation.

Lower-extremity arteriovenous access for haemodialysis: a systematic review.

BACKGROUND: The lower extremity is increasingly used as an access site in end-stage renal disease patients. However, reports present conflicting results, creating confusion regarding the feasibility and outcomes. Our objective is to review the available literature and analyse the patency rates and complications of various types of lower-extremity arteriovenous access. METHODS: An Internet-based literature search was performed using MEDLINE to identify all published reports on lower-extremity vascular access. The analysis involved studies comprising at least 10 arteriovenous accesses with both inflow and outflow vessels in the lower extremity, and reporting on patency rates and access-related complications. The weighted mean patency rates were calculated, and the chi-square (chi(2)) test was used to evaluate the differences in the complication rates in the subgroups of patients identified. RESULTS: Three main types of lower-extremity vascular access were identified: the upper thigh prosthetic, the mid-thigh prosthetic and the femoral vein transposition arteriovenous access. There are limited data on saphenous vein loop grafts, which report poor results. The weighted mean primary patency rates at 12 months were 48%, 43% and 83%, respectively. The weighted mean secondary patency rates at 12 months were 69%, 67% and 93%, respectively. Access loss as a result of infection was more common in upper thigh and mid-thigh grafts than femoral vein transposition arteriovenous access (18.40%, 18.33% vs. 1.61%; P<0.05). Ischaemic complications rates were higher in autologous than prosthetic arteriovenous access (20.97% vs. 7.18%, P<0.05). CONCLUSIONS: Lower-extremity vascular access has acceptable results in terms of patency, with femoral vein transposition having better patency rates than femoral grafts. Autologous access is associated with less infective complications, however, at the expense of increased ischaemic complications rates. Further research with randomised trials is required to assess the outcomes of lower-extremity vascular access.

Letters to the editor: definitely not children of a lesser god.

Letters to the editor are brief texts that are published in a special section of medical journals. There are two types of letters to the editor: the observation and the comment. The former presents original work, while the latter constitutes criticism on work already published in the same journal. Although short, letters to the editor require as much effort and discipline in writing as, indeed, any other manuscript. Clarity and brevity should be their principal values. It is also important to comply with the journals' instructions for correspondence. Thus, eloquent letters to the editor may promote knowledge and enable fruitful exchange of ideas.

Arterial spasm mimicking superficial femoral artery trauma. Case report.

The existence of traumatic arterial spasm in large arteries is questionable in current literature. We report a case of a 19-year old man with comminuted unstable femur fracture who presented with an ischemic foot. Localized arterial spasm was revealed in the middle portion of the superficial femoral artery triggered by the external pressure of a spicular bone segment was revealed by arteriography. Complete resolution of ischemic symptoms followed fracture reduction. Traumatic arterial spasm although rare does exist.

Risk factors for ipsilateral reamputation in patients with diabetic foot lesions.

This study aimed to examine the rates and risk factors for ipsilateral re-amputation in 121 patients with diabetic foot and prior amputation. Twenty-six (21.5%) patients required re-amputation during a mean follow-up of 18 months. Most re-amputations were performed within the first 6 months of the initial amputation. Re-amputation was more common among patients in whom the initial amputation had only affected one or two toes. Age (hazard ratio: 1.06) and heel lesions (hazard ratio: 2.69) were significantly associated with re-amputation. There is a high risk of re-amputation in the diabetic foot, especially within the first 6 months of the initial amputation, mainly due to poor selection of the original amputation level in an effort to save a greater part of the lower extremity. Patients 70 years and those with heel lesions are at greatest risk of re-amputation.

Transposed brachial-basilic arteriovenous fistulas versus prosthetic upper limb grafts: a meta-analysis.

BACKGROUND: Controversy exists regarding the best type of arteriovenous (AV) fistula to be formed in secondary and tertiary access procedures when primary fistulas have failed. This meta-analysis aimed to compare transposed brachial-basilic AV fistulas (BBAVFs) with upper limb AV prosthetic grafts. METHODS: A literature search of the MEDLINE and SCOPUS databases was performed to identify comparative studies reporting outcomes for both BBAVFs with upper limb AV prosthetic grafts. Meta-analysis techniques were applied to identify differences in outcomes between the two groups regarding primary and secondary 1-year failure rates. RESULTS: Eleven relevant studies, involving 1509 patients, met the inclusion criteria and were incorporated in the final analysis; however, only one was randomised controlled trial. The pooled odds' ratio (OR) estimate for the primary and secondary failure rates at 1 year was 0.67 (CI 0.41-1.09) and 0.88 (CI 0.69-1.12), respectively, showing no difference in the outcome between the two groups. The re-intervention rate was higher for prosthetic grafts (0.54 per BBAVF versus 1.32 per graft). In a small subgroup of two studies comparing BBAVFs with forearm grafts the pooled estimate for 1-year primary failure rate was in favour of the BBAVF group (OR 0.3, CI 0.15-0.58, p=0.0004) suggesting that forearm grafts were inferior having a 3-fold risk of failure at 1 year. CONCLUSION: This analysis supports the use of BBAVF early in difficult access cases prior to the use of prosthetic grafts. However, the latter conclusion is debatable due to heterogeneity, small size and non-randomised design of the included studies.

Writing a case report: polishing a gem?

Case reports describe patient cases which are of particular interest due to their novelty and their potential message for clinical practice. While there are several types of case reports, originality and clinical implications constitute the main virtues by which case reports are judged. Defining the educational message and choosing the right audience are vital steps in the process of writing. Generally, a case report is structured, its main components being the abstract, the introduction, the case description and the discussion. Guidelines and tips for writing case reports are not enough for making a successful author, but they help, especially less experienced doctors, to exercise and improve their writing. If properly prepared, case reports can still communicate new observations in an interesting and pleasant way, thereby enriching our knowledge, even in the era of evidence-based medicine.

Changes in blood flow of anterior and middle cerebral arteries following carotid endarterectomy: a transcranial Doppler study.

AIM: The aim of the present study was to evaluate the changes in blood flow of anterior and middle cerebral arteries following carotid endarterectomy, using transcranial Doppler (TCD) flow studies. PATIENTS AND METHODS: This study included 100 patients (72 men, mean age 65 years) who underwent carotid endarterectomy because of high-grade carotid stenosis or symptoms of ischemic stroke. Endarterectomy was performed by a distal shunt between the common carotid and internal carotid arteries. Blood flow in the anterior and middle cerebral arteries was assessed by TCD preoperatively and also in the postoperative period (1st and 4th day; 1st, 6th, and 12th month). Collateral circulation in the Willis circle was evaluated by common carotid compression. RESULTS: Patients with bilateral carotid stenosis > or =70% exhibited a significantly increased flow velocity in the ipsilateral anterior cerebral artery (ACA), middle cerebral artery (MCA), and in the contralateral ACA. Patients with entirely occluded contralateral internal carotid artery showed the most pronounced changes in cerebral hemodynamics. Blood flow velocities returned to the preoperative values at 1 to 12 months following endarterectomy. Hyperperfusion syndrome was manifested in 14 patients, who exhibited significantly higher flow velocities in the ipsilateral MCA compared with asymptomatic patients. CONCLUSIONS: A transient bilateral increase of blood flow velocity in the anterior part of the Willis circle may often occur in the immediate postoperative period following carotid endarterectomy. Although its clinical significance is not entirely understood, this increase may be associated with cerebral hyperperfusion syndrome.

Lower extremity compartment sindrome following coronary artery bypass.

Compartment syndrome is a constellation of symptoms and signs associated with abnormally elevated tissue pressure in the skeletal muscle of the extremities. It is manifested in anatomic locations where muscles are enveloped in fasciae. The case of a lower extremity compartment syndrome in a 71-year-old male patient who underwent coronary artery bypass grafting (CABG) and simultaneous aortic valve surgery is reported. Preoperative evaluation revealed severe peripheral vascular disease. The patient underwent triple CABG using the left internal thoracic artery and two vein grafts. The right great saphenous vein was used for these vein grafts. The aortic valve was replaced with a biologic prosthesis. On postoperative day 1, the patient complained of pain and oedema in the right calf. The next day, symptoms worsened, with marked sensory loss, motor weakness and foot drop in the affected limb. Triplex ultrasonography excluded deep vein thrombosis. Compartment syndrome was diagnosed and successfully managed by fasciotomy. This case illustrates that compartment syndrome may, although rarely, be a complication of CABG.

Ankle-brachial index: a surrogate marker of microvascular complications in type 2 diabetes mellitus?

AIM: The aim of this study was to investigate the potential role of ankle-brachial index (ABI) as a marker of microvascular disease in patients with type 2 diabetes mellitus. METHODS: This study included 126 type 2 diabetic patients (64 male and 62 female) with an age of 66.6+/-5.3 years (mean+/-SD) and diabetes duration of 13.2+/-4.1 years. ABI was measured with a Doppler device. The exclusion criterion was the medial arterial calcification. Patients were also examined for microalbuminuria, retinopathy and peripheral neuropathy. RESULTS: ABI was significantly lower in patients with microalbuminuria than in those without microalbuminuria (0.91+/-0.17 vs 1.05+/-0.13, P=0.004), in patients with retinopathy than in those without retinopathy (0.91+/-0.18 vs 1.06+/-0.1, P=0.005), as well as in patients with neuropathy than in those without neuropathy (0.94+/-0.17 vs 1.06+/-0.11, P=0.001). Sensitivity and specificity of ABI <0.9 were 48.8% and 87.9% respectively for microalbuminuria, 39.1% and 93% respectively for retinopathy and 47% and 90.7% respectively for neuropathy. In multiple regression analysis, significant predictor of microalbuminuria was diabetes duration (P=0.0014), significant predictor of retinopathy was diabetes duration (P=0.001), while significant predictors of neuropathy were diabetes duration (P=0.001), male sex (P=0.001) and presence of retinopathy (P=0.047). CONCLUSION: ABI is significantly lower in patients with than in those without microvascular complications of type 2 diabetes. An ABI <0.9 has a low to modest sensitivity, but a high specificity for the diagnosis of these complications. Our results suggest a potential role for ABI as a surrogate marker of microvascular complications in type 2 diabetic patients.

The role of hemodynamic measurements in the management of venous and ischemic ulcers.

There is a need for quantitative investigations in the vascular laboratory to manage lower extremity ulcers. The majority of leg ulcers are of venous (45%-60%) or arterial origin (10%-20%). Despite the increasing complexity of new devices used in vascular surgical practice, the anklebrachial pressure index (ABPI) remains the cornerstone for the differential diagnosis of ischemic ulcers. The toe-brachial pressure index and the pole test represent attractive alternative tests especially in patients with diabetes. Color flow Doppler imaging (CFDI) is advantageous over ABPI in cases in which wounds and ulcers prevent the use of a cuff by virtue of their size or location; additionally CFDI technology can detect nonflow limiting lesions, lesions to nonaxial arteries such as the deep femoral artery, or lesions limited to a single tibial artery. Continued improvements in the accuracy of CFDI have prompted some vascular surgeons to replace contrast arteriography in distal bypass procedures. Transcutaneous partial oxygen tension measurement (TcPO(2)) is another noninvasive method that is reliable to select the level of amputation and recommended to determine tissue viability in critically ischemic limbs and in the management of the diabetic foot. CFDI has revolutionized the diagnostic approach to venous disorders and it is considered the gold standard for the assessment of the venous system of the lower limb, causes minimal inconvenience to patients, and is easily repeatable, but it is considered highly operator dependent. Various plethysmography techniques are of limited application in ulcer investigations, because of their difficulty to calibrate signal, unless time measurements such as the postexercise refilling time are used.

Popliteal artery pseudoaneurysm after total knee replacement.

We report the case of a popliteal pseudoaneurysm following total knee replacement. A 70-year-old woman underwent total left knee replacement because of severe osteoarthritis. Eight days later she presented with oedema and pain in her left calf She had palpable foot pulses on the left leg and the ankle-brachial index was 0.98. The patient was treated for deep vein thrombosis. Two days later her calf pain and oedema deteriorated and her distal pulses were no longer palpable, while she developed limb coldness and paraesthesia, and the ankle-brachial index dropped to 0.4. Sonography was urgently performed indicating a large popliteal artery aneurysm (5.8 x 6.9 x 7.2 cm), confirmed by angiography. The patient was managed with removal of a 3.5 cm long segment of the popliteal artery and reconstruction with synthetic graft (PTFE 6 mm). Her condition soon improved and the patient is capable of walking approximately 1 km per day at 18-month follow-up.

Diagnostic criteria and treatment of Buerger's disease: a review.

Buerger's disease is an inflammatory occlusive disorder affecting the small and medium-size arteries and veins of young, predominantly male, smokers. The disorder has been identified as an autoimmune response triggered when nicotine is present. Tobacco abuse is the major contributing risk factor; however, smoking seems to be a synergistic factor rather than the cause of the disease. The traditional diagnosis of Buerger's disease is based on 5 criteria (smoking history, onset before the age of 50 years, infrapopliteal arterial occlusive disease, either upper limb involvement or phlebitis migrans, and absence of atherosclerotic risk factors other than smoking). As there is no specific diagnostic test and an absence of positive serologic markers, confident clinical diagnosis should be made only when all these 5 criteria have been fulfilled although not universally accepted. The angiographic findings in Buerger's disease ("corkscrew," "spider legs," or "tree roots") are helpful but not pathognomonic. A wide spectrum of medical or surgical therapeutic options have been proposed; however, total abstinence from tobacco use remains the only means of stopping the disease progression. The initial management of patients with Buerger's disease should be conservative. Because several arteries may be unaffected, claudicants should be encouraged to walk, whereas patients with "critical" ischemia should be admitted for bed rest in the hospital. Bypass grafting is seldom an option, as the location of the lesions distally leaves little to bypass because of lack of target vessels. A literature review revealed only a few series reporting vascular reconstruction (mainly femorodistal bypasses) in Buerger's disease. Bypass patency rates were suboptimal; however, the corresponding limb salvage rates were satisfactory. A possible explanation is that patent grafts, even over a short period of time, are sufficient to allow healing of ulcers in patients with Buerger's disease.

Peroneal artery pseudo-aneurysm following blunt injury.

The peroneal artery is injured less frequently than the popliteal and tibial arteries, because of its anatomical relationships. Pseudo-aneurysm of the peroneal artery due to a blunt injury is a rare complication. These injuries are usually occult, but more have been identified with the introduction and increasing use of angiography, following a high clinical suspicion of the trauma team involved. We report a case of peroneal artery false aneurysm following blunt trauma, presented with intermittent haemorrhage. In trauma, isolated peroneal artery pseudo-aneurysms, although rare, may occur. Early diagnosis can be confirmed by angiography and when less-invasive procedures cannot be applied, a posterior approach is an attractive surgical option in the management of proximal peroneal artery traumatic lesions.

Lack of evidence for use of heparin-bonded grafts in access surgery: a meta-analysis.

The aim of this study was to evaluate the efficacy of heparin-bonded vascular grafts to offer improved outcomes compared with standard prosthetic grafts in access surgery. A systematic review and meta-analysis was performed and eight studies (seven observational studies and one randomized controlled trial) were included. The pooled 6-month and 1-year primary patency was not significantly different between heparin-bonded arteriovenous (AV) grafts and standard prosthetic AV grafts in seven studies reporting on 1,209 access procedures. The assisted primary patency and secondary patency at 1-year was not significantly different either. Heparin-bonded AV grafts offer no distinct advantage over standard prosthetic AV grafts and their preferential use in access surgery cannot be recommended based on the available evidence.

The significance of medial sural artery integrity in popliteal artery trauma: a case report.

Two patients with popliteal artery trauma who underwent secondary amputations due to refractory calf sepsis despite a patent arterial repair are presented in this case report. The medial sural artery, the main arterial supply of the medial head of the gastrocnemius, was surgically severed in both patients owing to the use of a continuous medial incision from the supra level to infragenicular level. The compromised arterial supply of the medial head of the gastrocnemius muscle may have contributed to the devitalization of the muscle and the subsequent calf sepsis, and it is speculated that this was related to the unfavorable outcome.

Indications for surgical treatment of angioaccess-induced arterial "steal".

BACKGROUND: Arterial "steal" is a well-known complication following proximal arteriovenous (AV) fistula, but its manifestations comprise a wide spectrum of symptoms and there are no clear indications for those patients who need surgical repair. STUDY DESIGN: Among 180 consecutive AV fistulas of various configurations, with the brachial artery as the donor artery in all patients, 111 patients were studied retrospectively (group A) and 69 patients were studied prospectively (group B). Patient records were reviewed in group A, and the decision for surgical correction of limb-threatening steal was based on clinical grounds only. In group B, all patients were followed prospectively; postoperative systolic blood pressure measurements were obtained, and a systolic pressure index (SPI) was calculated (postoperative forearm systolic pressure divided by contralateral forearm systolic pressure). In patients with an SPI < 0.6, nerve conduction studies (NCS) were performed. The decision for operation in this group was based on clinical examination, SPI, and NCS. RESULTS: Seven patients were operated on for steal-induced limb-threatening ischemia; in all seven patients, ischemia developed immediately after access construction. One additional patient with mild symptoms and deterioration in repeated NCS was considered a candidate for ischemic monomelic neuropathy and was successfully operated on 1 month later. The ligation-bypass technique was used in all patients, consisting of arterial ligature distal to the takeoff of the graft and short arterial bypass from a point proximal to the inflow of the access to a point just distal to ligation. In 94% of the patients, some degree of distal ischemia was detected (SPI < 0.8); patients with SPI < 0.5 were most likely to have impaired NCS. CONCLUSIONS: Steal-induced limb-threatening ischemia necessitating immediate surgical repair occurred in 3.9% (7 of 180) of our patients. The decision for surgical correction of steal should be based on clinical examination. Nerve conduction studies may be useful in patients who have an SPI value < 0.5 to detect candidates who might develop ischemic monomelic neuropathy. In similar patients, surgical treatment of steal should be offered.